Substructural And Vibrational Properties Of DNA

In the 21st century, the ion irradiation breeding, heavy ion and proton cancer is the leading edge of science. At the same time, irradiation, ion irradiation in the environment and space radiation in the universe, medical lead to new varieties of organisms to produce more and more widespread concern. In theory, the objects from the graduate students in molecular and cellular levels of ionizing radiation damage is the basis of radiation biology and radiation medicine, involves an important frontier of nuclear physics, medicine, chemical and biological interdisciplinary. Molecular biology, nucleic acid is mainly to study the structure and function of nucleic acids. In recent decades, due to the development of theory and experiment, the field has become one of the richest areas in the molecular biology content. Deoxynucleotide, and nucleotides are an important part of DNA and RNA molecules. In radiation biology and radiation medicine, DNA and RNA is the major target of ionizing radiation induced cell killing or transformation. Rays act on the body, from the beginning of exposure to biological effects (cancer, etc.) is a complex process, the impact of its structure is more complex, a wide variety of radiation product. DNA and RNA damage can affect one of its component units, but only the loss or change that has genetic consequences of the nucleic acid bases. Therefore, the study clearly physical and chemical properties of nucleic acid bases before and after radiation is of great significance for the radiation damage of DNA and RNA.The study of the molecular vibrational spectroscopy is an important tool for research in the molecular characterization. Biomolecules such as nucleic acid bases spectroscopic methods for the isolation of the surrounding environment or stable is very important to clarify the role of different biological functions of biological macromolecules. Two experimental methods often used in infrared and Raman spectra, as marked in the experimental study of Atomic and Molecular especially biological macromolecules in the experimental spectra is very difficult, given to understand the experimental spectrum by the theoretical calculations of the vibrational spectra, and to anticipate new The spectrum is of great significance. In the theoretical calculations, mainly including more accurate quantum chemical calculations and classical molecular dynamics method, including the semi-empirical quantum chemical calculations and abinitio methods, such as HF and DFT methods. Atomic number of the more biological molecules, computational quantum chemistry methods is very alarming, and need to introduce a scale factor abinitio method calculations increased uncertainty, while the semi-empirical potential molecular dynamics, can overcome the deficiencies of the above model Department, the study of the vibrational spectra and the nature of the biological macromolecules can be a reliable and effective method.Molecular dynamics is an increasingly wide range of applications in the study of biological molecules, and many studies have shown that the molecular dynamics of biological macromolecules is feasible. But all these calculations did not give a molecular vibration mode and frequency, so we used semi-empirical potential molecular dynamics method to study the vibrational properties of uracil molecules. Through the calculation of uracil molecules in the molecular dynamics trajectories, speed, acceleration, in which atomic force size and direction of motion, calculate the molecular vibration frequency, given the molecular potential energy of vibration spectral range-1185.5kcal/mol to-1183.5kcal/mol; solving molecular dynamics bond lengths, bond angles, and non-key can be done to extract every step of the three-dimensional diagram of the molecular space in the state of the molecular vibration frequency, calculation results in line with existing experimental data. Gives a more complete uracil molecular vibration modes and frequencies; consider biological molecules are in different biological temperatures, the temperature on their impact can not be ignored, so we use the semi-empirical molecular dynamics method to study and lists the temperature OK,20K,40K,60K,80K,100K, 150K,200K,250K potential vibration properties of the uracil molecule, the kinetic energy changes of the amplitude, found that the temperature of the uracil molecular structure and vibrational frequencies indeed have a major impact, we studied the thermal radiation (temperature effect) affect the nature of the uracil molecule.